One summer night in Shanghai, Zong Ying encounters a mysterious man in her home who claims to time travel nightly from 1937 to the present. As an attorney from the Republic of China, he provides proof of his identity, but Zong Ying initially dismisses his story—until he vanishes before her eyes.

1936年与2016年的时空，交错于上海的一幢699号老公寓。这是一场命中注定、浪漫至极的奇迹爱情。它连接时空两端的上海，将两个被爱遗忘的人，紧紧连在一起。当繁华的十里洋场里暗藏着重重危机，两个相爱的人，该如何相守一生？